Montgomery  waddell



(No ModeL) M. WADDELL.

BLEOTRIG CURRENT INDICATOR.

No. 353,649. D Patented Nov. 30, 1886.

N. PFIERS, Phulo-Lfllwgrapher. Wnhingtnn. n. a

UNITED STATES PATENT OFFICE.

MONTGOMERY W'ADDELL, OF OOBOURG, ONTARIO. CANADA, ASSIGNOR TO HIMSELFAND WILLIAM S. ANDREWS, OF NEW YORK, N. Y.

ELECTRIC-CURRENT INDICATOR.

SPECIFICATION forming part Of Letters Patent No. 353,649, dated November30, 1886.

Application filed April 8, 1885. Serial No. 161,559. (No model.)

To aZZ whom, it may concern:

Be it known that I, MONTGOMERY WAD- DELL, of Oobourg, in the Province ofOntario and Dominion of Canada, have invented a new 5 and usefulImprovement in Electric-Current Meters; and I do hereby declare that thefollowing is a full and exact description thereof, reference being hadto the accompanying drawing, and to the letters of reference markedthereon, making a part of this specification.

My invention relates to an automatic current or Ampere meter formeasuring an electric current.

It consists of a pendulum in the form of a quadrant or sector having acurved bar of soft iron projecting from the lower end of one of itsarmsin an are having the pivot of the pendulum as its center, and of afixed rigid coil,

preferably of copper wire, curved in an are whose radius corresponds tothat of the are described by the iron bar, and which is mounted in frontof said bar, so that the latter may swing freely in and out of the coilwhen vibrating upon its axis. \Vhen the coil is included in an electriccircuit, the vibrating bar will be drawn more or less into the coilbythe attraction of the currenttand the extent of the movement therebyimparted to the pendulum will afford an accurate indication of theintensity of the current.

The use of a pendulum for carrying the curved solenoid-core makes themeter or indicator sensitive, accurate, and uniform in its action, andcauses it to maintain its position at zero by being at that time in acondition of stable equilibrium. The penduluinis also provided with aweight, adjustable, so as to change its center of gravity. The effect ofthe adj ustment of this weight is to vary the normal or zero position ofthe pendulum and to adjust the initial relation of the solenoid-corewith the stationary coil. The curved solenoid-coil, which attracts thecore formed by the curved bar of soft iron, is composed of open rigidconvolutions of bare metal held apart by their rigidity and insulatedfrom each other only by the intervening air-spaces. This enables thecoil to be connected directly in the main line of the circuit thecurrent of which is to be measured or indicated without a detrimentalwaste of current. This feature adds largely to the sensitiveness of theinstrument, and, in connection with a pendulous curved core and anadjustable weight for changing the center of gravity of the pendulum,makes a highly efficient instrument for current indication.

In the accompanying drawing, A B B represent a frame or pendulum in theform of a sector, which is pivoted at its angle 0, so as to swing withthe utmost freedom in a vertical 6o plane.

The pivotal suspension of the sectoral frame is made as delicate aspossible, so that it shall vibrate under the least impulse. A bar, D, ofsoft iron is fixed to the lower end of one of the side bars, B, of thependulum, so as to project therefrom toward the opposite side bar, B, ina curve constituting an are having the pivot O at its center." This ironbar projects about midway between the extremities of the bars B B, andis there preferably joined to a rod, E, of brass or other non-magneticmaterial, which, extending in the same are, connects it to the oppositearm of the pendulum.

I F is the solenoid-coil, intended to be con- 5 nected directly in themain line of the circuit, and composed of bare copper wire sufficiently,large to form open rigid convolutions, the coil being of low resistanceand maintaining its shape and the separated condition of itsconvolutions by its rigidity. It is large enough to encircle the wholelength of the copper rod, and to terminate at or about the point of itsjuncture with the iron rod. The internal diameter of this coil F islarge enough to permit the soft-iron rod or coreD to swing freely intoit without contact. The non-magnetic supporting-rod E may be dispensedwith. leaving the end of the iron core D to project free into the coilF, the coil being curved in an arc cor- 9o responding with thatdescribed by the core D, so that the latter may swing freely into thecoil.

The vibration of the pendulum may be indicated by means of a pointer orindex-finger 5 fixed upon the transverse bar H of the frame, so as tomove with the pendulum over a scale fixed beneath it; or a rack, t i,may be formed upon the edge of said bar H, to engage a pinion, K,rotating upon a fixed arbor, and an I00 l traveling recording-sheet bymeans of two index-pointer, L, be fixed-to the pinion to projecttherefrom and sweep over the face of a dial, M, having a suitable scalemarked upon its periphery, whereby the least movement of the pendulum ismade apparent and is readily measured.

For the purpose of adjusting the pendulum or frame A B B so that the endof the core D shall barely enter the coil F when the pendulum is at restand its index is at the zero-point of the scale, one of its arms, B,maybe th readcd to carry a counterbalance-weight in the form ofa nut, G,which is adapted to screw up or down upon the arnrand whose posit-ionwill determine the center of gravity ofthe penduln m.

In the use of the device the coil F is placed in the electric circuitwhose current is to be measured. The attraction of the electric currentfor the iron bar D will cause itto be drawn into the coil more or less,according to theintensity of the current, and the consequent oscillationof the pendulum, as indicated upon the scale, will afford a measurethereof. The position of the pendulum when it is at rest and there is nocurrent in the circuit serves to indicate the zero or initial point forthe scale.

Iam aware that it has been proposed to produce a recording electricmeter by the employment of a traveling recording-sheet moved byclock-work, and that it has been proposed to vary the position of astyle laterally'of such curved solenoid-cores attached to the oppositeends of a centrally-pivoted horizontal arm or walking-beam and acted onbytwo curved solenoid-coils, the cores being retracted to the zeropointby a coiled spring, and the coils in attracting such cores being opposedby the retracting force of the said coiled springs; but with such aninstrument it is evidently immaterial whether the cores work in avertical plane or in a horizontal plane, and the instrument, in fact,instead of being a pendulum in- -strument, like mine, is simply apivoted core attracted by a coil and retracted by a spring, which hasnever been found a practical form of apparatus for current indication.

I claim as my invention- 1.' In a electric-current meter or indicator,

the combination, with a pendulum, of a horizontally-projecting curvedsolenoid-core carried by such pendulum and a curved coil in an electriccircuit acting upon such core, sub-' stantially as set forth.

2. In an electric-current meter orindicator,

the combination, with a pendulum in the form of asector,ofahorizontally-projecting curved solenoid-core carried by such pendulumand a curved coil in an electric circuit acting upon such core,substantially as as set forth.

4. In an electric-current meter orindicator,

the combination of two arms projecting below and diverging radially froma pivotal center,

and forming a pendulum. with an adjustable weight carried by one of sucharms, a horizontally-projecting curved solenoid-core carried by suchpendulum, and a curved coil acting upon such core, substantially as setforth."

5. In an electric-current meter or indicator, the combination, with apendulous curved solenoid-core, of a fixed curved solenoid-coil adaptedto be placed directly in the'main line, and composed of open rigidconvolutions of bare metal, substantially as set forth.

6. In an electric-current meter orindicator, the combination, with apendulum, of a horizontally-projecting curved solenoid-core carriedthereby, a fixed curved solenoid-coil composed of open rigid convolutions ofbare metal, and a weight on the pendulum, adjustable, so asto change the center ofgravity ofsuch'pendulum, substantially as setforth.

, 7. In an electric-current meter, the combination of a'rigid curvedcoilforming part of the circuit whose current is to be measured orindicated, a similarly-curved core having an arm extending upwardly fromits outer end, a curved non-magnetic bar extending 'from the inner end,and an arm extending upwardly from said non-magnetic bar, said upwardarms being joined at their upper ends and pivotall y supported thereat,substantially as set forth.

8. The combination, with an iron core pivoted to swing as a pendulum andcurved in an are described about said pivot as its center, and with acoil serving as a conductor for an electrical current, and which iscurved in its length and fixed in position to permit the core to swingtherein, of a transverse rack bar moving with the core and gearing intoa pinion carrying an indicator fitted to move over a suitable scale ordial, substantially in the manner and for the purpose herein set forth.

In testimonywhereofI have signed my name to this specification in thepresence of two subscribing witnesses.

MONTGOMERY W'ADDELL.

lVitnesses: 4 JOHN A. ELLIS, A. B. MOORE.

